JPH0352503B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a colorless dye-developer ink that can provide dark, clear and sharp handwriting, and that can be easily erased using a desensitizer made of a polar compound. It is something. A colorless dye-developer ink in which a color developer having a phenolic hydroxyl group and a colorless electron-donating organic compound (colorless dye) that develops color with the color developer are dissolved in a solvent that does not inhibit this color reaction. A patent application has already been filed in the same application as the present application (Japanese Patent Application No. 2122257/1982 = Japanese Patent Application No. 29102/1998). This ink has a deep color similar to normal oil-based ink, so it can produce dark and clear handwriting, and it also has the advantage of being easily erased using a polar compound that has a desensitizing effect. . Many types of compounds can be considered as color developers with phenolic hydroxyl groups that can be used in such colorless dye-color developer inks, but the stability of the color developer present in handwriting depends on the vertical shape of handwriting. Subsequent research has revealed that it has a significant impact on prison performance. Among the many color developers, novolac type phenolic resin in particular exists stably without being volatilized or removed by heat, light, water, etc. in the outside world, so the density of the handwriting when writing is resistant to fading. Furthermore, when a novolak type phenolic resin is used as a color developer, aromatic alcohol or ethylene glycol monophenyl ether can be used as a solvent for the color developer and colorless dye, and the solvent does not inhibit the color development reaction. It was discovered that it can be effectively used as
issue). However, even with ink using the above-mentioned novolac type phenolic resin as a color developer, if the handwriting is exposed to sunlight for a long time,
There is a slight tendency for color fading, especially when phthalide-based dyes such as crystal violet lactone are used as colorless dyes in the ink, and there is still room for improvement. . Therefore, the present inventors conducted further research with the aim of providing a colorless dye-developer ink that does not fade even when exposed to sunlight for a long period of time. A metal salt of an aromatic carboxylic acid is added to an ink obtained by dissolving a colorless dye that develops color with the developer in a solvent consisting of an aromatic alcohol and/or ethylene glycol monophenyl ether.
The present invention was completed based on the discovery that the above object can be achieved by dissolving it. As the colorless dye, which is the main component of the colorless dye-developer ink of the present invention, a colorless electron-donating organic compound generated by a novolak type phenolic resin developer can be used, but as described above, In particular, when an aromatic carboxylic acid metal salt is added to an ink that uses a phthalide-based color-forming organic compound, such as crystal violet lactone or malachite green lactone, as a colorless dye, the handwriting may be exposed to sunlight for a long time. Fading resistance is significantly improved. However, other colorless dyes, e.g.
-dimethylamine-6-methoxyfluorane,
3,6-diethoxyfluorane, 1,2-benz-6-diethylaminofluorane, 2-anilino-3-methyl-6-pyrrolindino-fluorane,
3′,6′-bis-(diethylamino)spiro-(phthalane-1,9′-xanthine), 1,1-bis-(p
Fluorane-based color-forming organic compounds such as -aminophenyl)-phthalane and spiropyran-based color-forming organic compounds such as di-β-naphtho-spiropyran, xantho-β-naphtho-spiropyran, and benzo-β-naphtho-isospiropyran were used. Even when an aromatic carboxylic acid metal salt is added to the ink, the effect of improving the fading resistance when handwriting is exposed to sunlight for a long time is observed. The amount of colorless dye used is 10 to 10% of the total amount of ink.
About 30% by weight is preferable in terms of ink concentration and ink dissolution stability. In addition, the ratio of novolak type phenolic resin developer and colorless dye is 1:3~
A ratio of 10:1 is more preferable in terms of color density and color stability of the ink. In the present invention, aromatic alcohol and/or ethylene glycol monophenyl ether can be preferably used as a solvent for dissolving a color developer, a colorless dye, and an aromatic carboxylic acid metal salt as an additive. These solvents are polar compounds that have a desensitizing effect, and therefore, at first glance, they cannot be used as ink solvents because they inhibit the color development reaction in colorless dye-developer type inks. Nevertheless, the reason why these polar solvents can be used as effective solvents in the present invention is that they dissolve the color developer and the colorless dye very well, promoting the color-forming reaction between them, and therefore the polar solvent It is thought that the color developing effect of the color developer is superior to the desensitizing effect, and a dark and clear colored ink is obtained. Examples of the aromatic alcohol include benzyl alcohol, β-phenylethyl alcohol, 3-phenyl-1-propanol, 4-phenyl-2-butanol, and methylphenyl carbinol. On the other hand, among the glycols, ethylene glycol monophenyl ether was particularly used because its desensitizing effect is weaker than that of other glycols. These solvents may be used alone or in combination of two or more. The amount of solvent used is preferably about 25 to 50% by weight based on the total amount of ink from the viewpoint of stability and fluidity of the ink. As the aromatic carboxylic acid metal salt added to the above-mentioned colorless dye-developer ink, those having at least one hydroxyl group in the aromatic ring, particularly metal compounds having a hydroxyl group in the ortho position, can be preferably used. Such metal salts of aromatic carboxylic acids are stable compounds that substantially do not decompose or sublimate in a normal atmosphere. Examples of aromatic carboxylic acids include salicylic acid, 5-tert-butylsalicylic acid, 3-phenylsalicylic acid, and 3-methyl-
5-tert-butylsalicylic acid, 3,5-di-tert
-butylsalicylic acid, 3,5-diamylsalicylic acid, 3-cyclohexylsalicylic acid, 3-methyl-5-isoamylsalicylic acid, 5-isoamylsalicylic acid, 3,5-di-sec-butylsalicylic acid,
5-nonylsalicylic acid, 2-hydroxy-3-methylbenzoic acid, m-cresotic acid, 5,5'-methylenedisalicylic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxy Benzoic acid, anacardic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3
-phenyl-5-(α,α′-dimethylbenzyl)
Salicylic acid etc. can be used. Further, as the metal constituting the metal salt of these aromatic carboxylic acids, zinc, aluminum, tin, nickel, etc. can be used. These aromatic carboxylic acid metal salts may be used alone or in combination of two or more, and the amount added is 20% by weight or less based on the total amount of the ink. This is because if it exceeds 20% by weight, the compatibility with the ink will deteriorate and the stability as an ink will deteriorate. In addition, the ink of the present invention includes various additives commonly used to adjust the viscosity and lubricity of the ink.
For example, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, oleic acid, oleic acid ester, surfactant, etc. can be appropriately selected and used as required. Next, the method for manufacturing the ink of the present invention will be briefly described. Easily obtained by mixing in a device. In addition, when adding other additives as necessary, they may be added to the above components and mixed in the same manner. The ink thus obtained is stored in the ink storage part of conventionally used ballpoint pens, felt pens, felt-tip pens, markers, etc., supported by the pen shaft, and leached from the pen tip. It can be used as a brush. As can be seen from the above description, the ink of the present invention uses a novolac type phenolic resin as a color developer and an aromatic alcohol and/or ethylene glycol monophenyl ether that dissolves the color developer and colorless dye very well. It is a colorless dye-developer-based ink that uses as a solvent,
The goal is to create handwriting that is darkly colored, relatively solid, and difficult to fade or erase over time. By adding and dissolving aromatic carboxylic acid metal salts to this ink, the handwriting becomes more difficult to fade or erase over time. This prevents handwriting from fading when exposed to sunlight for a long period of time, and improves its resistance to fading. The present invention will be further explained below by giving Examples and Comparative Examples. Note that "parts" in Examples and Comparative Examples indicate parts by weight. Example 1 Novolac type phenolic resin "Tamanol PA" (manufactured by Arakawa Chemical Co., Ltd.) [Developer] 25 parts Crystal Violet Lactone [Phthalide colorless dye] 20 parts Benzyl alcohol [Solvent] 30 parts Ethylene glycol monophenyl ether [Solvent] 20 parts 5-tert-butylsalicylic acid zinc 5 parts The above formulation was dissolved by heating at 100°C for 1 hour, and a small amount of insoluble matter was removed by passing the mixture, and the ink of the present invention, which had developed a black color, was obtained. Obtained. This ink is used in a ballpoint pen (JIS S-6039-1980
E-type for fine print) and write on paper (JIS P-3201 writing paper A) using a drawing machine (load 200g, speed 7cm/sec, angle 70°), and record the resulting handwriting with a fade meter. The degree of discoloration was examined after 5 hours of exposure. The results are shown in Table 1. Comparative example 1 Novolac type phenolic resin “Tamanol PA”
30 parts crystal violet lactone 20 parts benzyl alcohol 30 parts ethylene glycol monophenyl tail 20 parts A blue ink having the above composition was prepared in the same manner as in Example 1 except that zinc 5-tert-butylsalicylate was removed. was adjusted, and the degree of discoloration of this handwriting was examined in the same manner as in Example 1. The results are shown in Table 1. The degree of fading of handwriting using a commercially available blue oil-based ballpoint pen was also examined in the same manner. Example 2 Novolak type phenolic resin “Tamanol PA”
25 parts fluoran colorless dye "BK-14" (manufactured by Yamada Chemical Industry Co., Ltd.) 20 parts benzyl alcohol 20 parts ethylene glycol monophenyl ether 30 parts 3-methyl-5-tert-butylsalicylate zinc 5 parts Each of the above ingredients A black ballpoint pen was prepared by blending in the same manner as in the example. The handwriting with this black ballpoint pen was examined in the same manner as in Example 1. The results are shown in Table 1. Comparative example 2 Novolac type phenolic resin “Tamanol PA”
30 parts Fluoran colorless dye "BK-14" 20 parts Benzyl alcohol 20 parts Ethylene glycol monophenyl ether 30 parts In the ink composition of Example 2, 3-methyl-5
A black ink having the above composition was prepared in the same manner as in Example 2, except that zinc -tert-butylsalicylate was removed, and the degree of fading of the handwriting was examined in the same manner as in Example 2. The results are shown in Table 1. At the same time, the degree of fading of handwriting using a commercially available black oil-based ballpoint pen was also examined.

[Table] As can be seen from Table 1, in the inks of Example 1 and Comparative Example 1 that used phthalide-based colorless dyes, the fading resistance of handwriting was significantly improved by the addition of aromatic carboxylic acid metal salts, and This improves the fading resistance of handwriting made with a blue oil-based ballpoint pen to a degree that is almost comparable to that of the original. In addition, Example 2 using a fluoran colorless dye
The inks of Comparative Example 2 and Comparative Example 2 generally have better fade resistance than those using phthalide-based colorless dyes, but
The addition of the aromatic carboxylic acid metal salt has been found to have an effect of improving the fading resistance of handwriting, and the fading resistance is approximately the same as that of handwriting made with a commercially available black oil ballpoint pen. On the other hand, an ink eraser consisting of 7.5 parts of N-vinylpyrrolidone-vinyl acetate copolymer [a desensitizer that is solid at room temperature], 89.5 parts of ethanol [a solvent], and 3 parts of high molecular weight polyvinylpyrrolidone was used with an oil-based marker (Pentel Co., Ltd.). M-10) parts were filled, and the above Example 1 was filled.
and the blue ink handwriting obtained in Comparative Example 1, and the black ink handwriting obtained in Example 2 and Comparative Example 2.
After rubbing it three times, I was able to completely erase all handwriting.

Claims (1)

[Claims] 1. A colorless dye obtained by dissolving a color developer made of a novolac-type phenolic resin and a colorless electron-donating organic compound that develops color with this color developer in a solvent made of aromatic alcohol and/or ethylene glycol monophenyl ether. - A colorless paint-developer ink, characterized in that a metal salt of an aromatic carboxylic acid is added and dissolved in the ink in an amount of 20% by weight or less of the ink.